+void\r
+modexDrawSprite(page_t *page, int x, int y, bitmap_t *bmp) {\r
+ /* draw the whole sprite */\r
+ modexDrawSpriteRegion(page, x, y, 0, 0, bmp->width, bmp->height, bmp);\r
+}\r
+\r
+void\r
+modexDrawSpriteRegion(page_t *page, int x, int y,\r
+ int rx, int ry, int rw, int rh, bitmap_t *bmp) {\r
+ word poffset = (word)page->data + y*(page->width/4) + x/4;\r
+ byte *data = bmp->data;\r
+ word bmpOffset = (word) data + ry * bmp->width + rx;\r
+ word width = rw;\r
+ word height = rh;\r
+ byte plane = 1 << ((byte) x & 0x03);\r
+ word scanCount = width/4 + (width%4 ? 1 :0);\r
+ word nextPageRow = page->width/4 - scanCount;\r
+ word nextBmpRow = (word) bmp->width - width;\r
+ word rowCounter;\r
+ byte planeCounter = 4;\r
+\r
+ __asm {\r
+ MOV AX, SCREEN_SEG ; go to the VGA memory\r
+ MOV ES, AX\r
+\r
+ MOV DX, SC_INDEX ; point at the map mask register\r
+ MOV AL, MAP_MASK ;\r
+ OUT DX, AL ;\r
+\r
+ PLANE_LOOP:\r
+ MOV DX, SC_DATA ; select the current plane\r
+ MOV AL, plane ;\r
+ OUT DX, AL ;\r
+\r
+ ;-- begin plane painting\r
+ MOV AX, height ; start the row counter\r
+ MOV rowCounter, AX ; \r
+ MOV DI, poffset ; go to the first pixel\r
+ MOV SI, bmpOffset ; go to the bmp pixel\r
+ ROW_LOOP:\r
+ MOV CX, width ; count the columns\r
+ SCAN_LOOP:\r
+ LODSB\r
+ DEC SI\r
+ CMP AL, 0\r
+ JNE DRAW_PIXEL ; draw non-zero pixels\r
+\r
+ INC DI ; skip the transparent pixel\r
+ ADD SI, 1\r
+ JMP NEXT_PIXEL\r
+ DRAW_PIXEL:\r
+ MOVSB ; copy the pixel\r
+ NEXT_PIXEL:\r
+ SUB CX, 3 ; we skip the next 3\r
+ ADD SI, 3 ; skip the bmp pixels\r
+ LOOP SCAN_LOOP ; finish the scan\r
+\r
+ MOV AX, nextPageRow\r
+ ADD DI, AX ; go to the next row on screen\r
+ MOV AX, nextBmpRow\r
+ ADD SI, AX ; go to the next row on bmp\r
+\r
+ DEC rowCounter\r
+ JNZ ROW_LOOP ; do all the rows\r
+ ;-- end plane painting\r
+\r
+ MOV AL, plane ; advance to the next plane\r
+ SHL AL, 1 ;\r
+ AND AL, 0x0f ; mask the plane properly\r
+ MOV plane, AL ; store the plane\r
+\r
+ INC bmpOffset ; start bmp at the right spot\r
+\r
+ DEC planeCounter\r
+ JNZ PLANE_LOOP ; do all 4 planes\r
+ }\r
+}\r
+\r
+\r
+void\r
+modexCopyPageRegion(page_t *dest, page_t src,\r
+ word sx, word sy,\r
+ word dx, word dy,\r
+ word width, word height)\r
+{\r
+ /* todo */\r
+}\r
+\r
+\r